The knee is very complex and, includes many components with many functions. The knee problems may be related to meniscus, pain, cartilage, shock absorption, synovial fluids, articular cartilage, ligaments/tendons and/or preserving normal biomechanics. Available therapy currently includes chronic synovial lubrication, acute synovial lubrication, meniscal protection, meniscal augmentation, partial meniscal replacement, total meniscal replacement, and partial or total knee prosthesis.
The menisci are crescents roughly triangular in cross section, covering one-half to two thirds of the articular surface of the corresponding tibial plateau. The outer rims of the menisci are convex and attached to the knee joint capsule. The inner edges are concave, thin and free. The anatomy of menisci and knee joints can be found in any anatomy book, for example, Gray's Anatomy of the Human Body, 20th edition, New York, Bartleby.com 2000.
The menisci extend the superior tibial surface, improving its congruency with the femoral condyles. Both menisci are fibrocartilaginous and wedge shaped in the coronal plane. The medial meniscus is crescent shaped, and the lateral meniscus is more circular. The superior portions of the menisci are concave, enabling effective articulation with their respective convex condyles, whereas the inferior surfaces are flat to conform to the tibial plateaus. Anterior and posterior meniscal horns attach to the intercondylar eminence of the tibial plateau. The coronary ligaments provide peripheral attachments between the tibial plateau and the perimeter of both menisci. The medial meniscus is also attached to the medial collateral ligament, which limits its mobility. The lateral meniscus is connected to the femur via the anterior and posterior meniscofemoral ligaments, which can tension its posterior horn anteriorly and medially with increasing knee flexion. The transverse ligament provides a connection between the anterior aspects of both menisci. The increased stability provided by the ligamentous attachments prevents the menisci from being extruded out of the joint during compression.
The knee joint is innervated by the posterior articular branch of the posterior tibial nerve and the terminal branches of the obturator and femoral nerves. Nerve fibers generally penetrate the joint capsule, along with the vascular supply and service the substance of the menisci.
Vascular supply is crucial to meniscal healing. The medial, lateral, and middle geniculate arteries, which branch off the popliteal artery, provide the major vascularization to the inferior and superior aspects of each meniscus. Only 10% to 30% of the peripheral medial meniscus border and 10% to 25% of the lateral meniscus border receive direct blood supply. The remaining portion of each meniscus receives nourishment only from the synovial fluid via diffusion or mechanical pumping. The latter mechanism derives from intermittent compression of the tissue during function. Mechanical pumping through joint flexion may be essential for continued nutrition.
The major meniscal functions are to distribute stress across the knee during weight bearing, provide shock absorption, serve as secondary joint stabilizers, provide articular cartilage nutrition and lubrication, facilitate joint gliding, prevent hyperextension, and protect the joint margins. During knee flexion, the femoral condyles glide posteriorly on the tibial plateau in conjunction with tibial internal rotation. The lateral meniscus undergoes twice the anteroposterior translation of the medial meniscus during knee flexion.
Type I collagen fibers provide the primary meniscal structural scaffolding; this predominance of type I collagen is one of the major differences between the menisci and hyaline, or articular, cartilage, which is composed of predominantly type II collagen. Three collagen fiber layers are specifically arranged to convert compressive loads into circumferential or “hoop” stresses. In the superficial layer, the fibers travel radially, serving as “ties” that resist shearing or splitting. In the middle layer, the fibers run parallel or circumferentially to resist hoop stress during weight bearing. Lastly, there is a deep layer of collagen bundles that are aligned parallel to the periphery.
Osteoarthritis (OA, also known as degenerative arthritis or degenerative joint disease) is a condition in which low-grade inflammation results in pain in the joints, caused by wearing of the cartilage that covers and acts as a cushion inside joints. As the bone surfaces become less well protected by cartilage, the patient experiences pain upon weight bearing, including walking and standing. Due to decreased movement because of the pain, regional muscles may atrophy, and ligaments may become more lax. OA is the most common form of arthritis. The main symptom is chronic pain, causing loss of mobility and often stiffness. “Pain” is generally described as a sharp ache, or a burning sensation in the associated muscles and tendons. Humid weather increases the pain in many patients.
OA commonly affects the hand, feet, spine, and the large weight-bearing joints, such as the hips and knees, although in theory, any joint in the body can be affected. As OA progresses, the affected joints appear larger, are stiff and painful, and usually feel worse, the more they are used throughout the day, thus distinguishing it from rheumatoid arthritis.
The primary osteoarthritis is caused by aging. As a person ages, the water content of the cartilage decreases, and the protein composition in it degenerates, thus degenerating the cartilage through repetitive use or misuse. Inflammation can also occur, and stimulate new bone outgrowths, called “spurs” (osteophyte), to form around the joints. Sufferers find their every movement so painful and debilitating that it can also affect them emotionally and psychologically.
The secondary osteoarthritis is caused by one or more of the following conditions or diseases: (1) congenital disorders, such as congenital hip luxation; (2) cracking joints; (3) diabetes; (4) Inflammatory diseases, such as Perthes' disease, and all chronic forms of arthritis (e.g. costochondritis, gout, and rheumatoid arthritis); (5) injury to joints; (6) ligamentous deterioration of instability; (7) hormonal disorders; (8) obesity; (9) osteopetrosis; (10) sports injury; and (11) surgery to the joint structures.
Heatley reported that repair of incisions in the central part of the meniscus on rabbits has demonstrated after surgical excision of the peripheral rim (J bone Joint Surg 1980; 62-B:397-402). Healing took place via a highly cellular but relatively avascular fibrous tissue stroma which proliferated from the synovial margin and invaded along the cut edge of the meniscus. Suturing facilitated this healing process by providing stability and possibly by supplying bridges for synovial cells to migrate onto the meniscus.
U.S. Pat. No. 4,344,193 issued on Aug. 17, 1982, entire contents of which are incorporated herein by reference, discloses a meniscus prosthetic device for a human knee joint so that the articulating cartilage in the knee totally remains intact. The prosthesis device translates between the articulating cartilages during normal knee movement. Insertion of the prosthetic device is accomplished by applying force on the ends of the device, thereby elastically spreading them, and placing the device between the tibial articulating cartilage and one of the femoral condyles. Prominences on the ends of the device may superiorly extend into the space defined by the femoral condyles, thereby securing the device in place.
U.S. Pat. No. 4,502,161 issued on Mar. 5, 1985, entire contents of which are incorporated herein by reference, discloses a prosthetic meniscus that is located between the natural articular surfaces of the bones of a joint. The prosthetic meniscus includes a body portion formed of a resilient material and further defines an extra-articular extension which is attached to the surface of the bone outside the joint. A reinforcing fabric or mesh is embedded in the resilient material to give the meniscus strength and shape.
U.S. Pat. No. 4,693,722 issued on Sep. 15, 1987, entire contents of which are incorporated herein by reference, discloses a prosthetic device for a temporomandibular joint comprising a prosthetic condyle and a prosthetic meniscus. The prosthetic condyle comprises two plates that are clamped about the ramus of the mandible wherein one of the plates extends upwardly into a convex surface thereby forming the condyle. The prosthetic meniscus comprising a resilient insert which is inserted into the joint capsule and has a reinforcing mesh embedded therein, and an extension for attaching the meniscus to the temporal bone.
U.S. Pat. No. 4,795,468 issued on Jan. 3, 1989, entire contents of which are incorporated herein by reference, discloses a mechanism and method for locking or securing a bearing insert to the base of a prosthetic implant. The prosthetic implant is for replacement of a portion of natural bone at the point of articulation. The implant includes a locking mechanism which enables the bearing insert to be removably secured to the base support. The locking mechanism includes a resilient locking clip which is predisposed on one side of either the bearing insert or the base support such that when the bearing insert and base support are assembled together, the clip extends between both the insert and the support to secure the two components together. To insert and/or remove the bearing insert from the support, the clip is caused to substantially fully recede into the component in which it is predisposed.
U.S. Pat. No. 4,919,667 issued on Apr. 24, 1990, entire contents of which are incorporated herein by reference, discloses a soft tissue implant in the form of a meniscus cartilage replacement for a patient. Appropriately shaped top and bottom layers sandwich therebetween at least one intermediate felted layer. A resilient bonding material coats the layers and holds same in a laminated condition. The top layer is contoured, to provide a wedge shaped cross section and a contoured three dimensional shape. A fabric member is bonded to the thickened edge of the laminant and is porous to invite ingrowth of patient tissue to anchor the implant eventually in place.
U.S. Pat. No. 5,067,964 issued on Nov. 26, 1991, entire contents of which are incorporated herein by reference, discloses an articular cartilage repair piece to substitute for a cut-out piece of damaged articular cartilage on a bone in an articulated joint. The repair piece includes a backing layer of non-woven, felted fibrous material which is conformable to flat and curved surfaces.
U.S. Pat. No. 5,092,894 issued on Mar. 3, 1992, entire contents of which are incorporated herein by reference, discloses a meniscus prosthetic device replacing natural components of a condylar joint. The body of the device is of biocompatible, deformable, flexible and resilient material for bearing compressive loads and for translating the loads to tensile stress. The tail of the device is also biocompatible material and extends as a continuation of the body from a first end to a second end of the body. The tail provides a continuous loop circuit for the propagation of hoop tensile stresses from the body, and provides stabilization of the knee joint and proprioceptive feedback. The prosthesis is implanted in a human knee in a position to take the place of a naturally occurring meniscus between the femoral condyle and the corresponding tibia, and the tail is placed into contact with bone associated with the knee.
U.S. Pat. No. 5,158,574 issued on Oct. 27, 1992, entire contents of which are incorporated herein by reference, discloses a prosthetic meniscus implanted in a human knee where it can act as a scaffold for regrowth of native meniscal tissues. The meniscus comprises a dry, porous, matrix of biocompatible and bioresorbable fibers, at least a portion of which may be crosslinked. The fibers include natural polymers, analogs, or mixtures thereof. The matrix is adapted to have in vivo an outer surface contour substantially the same as that of a natural meniscus. With this configuration, the matrix establishes an at least partially bioresorbable scaffold adapted for ingrowth of meniscal fibrochondrocytes.
U.S. Pat. No. 5,344,459 issued on Sep. 6, 1994, entire contents of which are incorporated herein by reference, discloses a prosthetic device which is arthroscopically implantable into a joint. The device has a ring or a pair of rings sized and shaped to fit within the joint. The ring or rings are comprised of a polymeric substance and may contain one or more compartments which are inflatable or expandable with air, a liquid or a semi-solid, through an arthroscope coupling means.
U.S. Pat. No. 6,046,379 issued on Apr. 4, 2000, entire contents of which are incorporated herein by reference, discloses an article of manufacture comprising a substantially non-immunogenic knee meniscal xenograft for implantation into humans. The invention further provides methods for preparing a knee meniscal xenograft by removing at least a portion of a meniscus from a non-human animal to provide a xenograft; washing the xenograft in saline and alcohol; and subjecting the xenograft to at least one treatment selected from the group consisting of exposure to ultraviolet radiation, immersion in alcohol, ozonation, and freeze/thaw cycling.
U.S. Pat. No. 5,171,322 issued on Dec. 15, 1992, entire contents of which are incorporated herein by reference, discloses a meniscus prosthetic device including a body and a tail. The body is of biocompatible, deformable, flexible and resilient material for bearing compressive loads and for translating the loads to tensile stress. The tail is also biocompatible material and extends as a continuation of the body from a first end to a second end of the body. The tail provides a continuous loop circuit for the propagation of tensile (hoop) stresses from the body, and provides stabilization of the knee joint and proprioceptive feedback.
U.S. Pat. No. 5,807,303 issued on Sep. 15, 1998, entire contents of which are incorporated herein by reference, discloses a device for relieving synovial fluid pressure in a capsule surrounding a body joint including a valve for placement in the capsule surrounding the joint for regulating passage of synovial fluid from the capsule. The valve can include a valve housing defining a passage between an interior and exterior of the capsule and a valve member disposed within the valve housing for regulating synovial fluid pressure within the capsule by permitting synovial fluid to drain from the capsule when a predetermined synovial fluid pressure is exceeded. The valve housing can be secured to the capsule with inlet and outlet flanges disposed at opposite ends of the housing and, additionally, by use of openings formed in the outlet flange to allow passage of sutures and to promote integral tissue fixation over time.
U.S. Pat. No. 6,005,161 issued on Dec. 21, 1999, entire contents of which are incorporated herein by reference, discloses a biodegradable device for facilitating healing of structural voids in bone, cartilage as well as soft tissue in the most preferred form including a porous macrostructure made from a biodegradable polymer and a chemotactic ground substance in the form of an RGD attachment moiety of fibronectin formed as a porous microstructure. For repair of articular cartilage, harvested precursor cells are secured to the biodegradable carrier which is shaped for press fitting into the articular cartilage lesion. In the most preferred form, biological modifiers such as transforming growth factor β and basic fibroblastic growth factor is incorporated in the biodegradable device to mediate cellular activity and regulate cellular functions.
U.S. Pat. No. 6,132,468 issued on Oct. 17, 2000, entire contents of which are incorporated herein by reference, discloses a flexible scaffold envelope which can be used to replace damaged cartilage. Designed for use in arthroscopic surgery, the envelope is sufficiently flexible to allow it to be rolled up or folded and inserted into a knee joint via a small skin incision. After the envelope is inserted into the joint, it is unfolded, positioned properly, and anchored and cemented to a bone surface. After anchoring, the envelope is filled via an inlet tube with a polymeric substance that will set and solidify at body temperature. During filling and setting, the surgeon can manipulate the exterior shape of the scaffold envelope, to ensure that the implant will have a proper final shape after the polymer has cured into fully solidified form.
U.S. Pat. No. 6,176,880, issued on Jan. 23, 2001, entire contents of which are incorporated herein by reference, discloses a reconstructive structure for a cartilaginous element having a plurality of superimposed layers of intestinal submucosa tissue compressed and secured together and shaped to provide a reconstructive structure having the anatomical shape of the cartilaginous element to be reconstructed is described. The method of forming the reconstructive structure includes superimposing the planar layers of the intestinal submucosa tissue, securing the layers to form a multi-layered structure and cutting the resulting multi-layered structure to the desired shape.
U.S. Pat. No. 6,352,558 issued on Mar. 5, 2002, entire contents of which are incorporated herein by reference, discloses a method of promoting regeneration of surface cartilage of a joint including the steps of forming punctures in a subchondral plate of an area of the joint to be treated, covering the puncture and the area to be treated with a chondrocyte-free patch made of a sheet of collagen membrane material without adding chondrocytes to the area to be treated, fixing the patch over the area to be treated, and allowing the area to be treated to regenerate cartilage without adding chondrocytes to the area to be treated.
U.S. Pat. No. 6,530,956 issued on Mar. 11, 2003, entire contents of which are incorporated herein by reference, discloses a load-sharing resorbable scaffold used to help transplanted chondrocytes or other cells generate new cartilage in a damaged joint such as a knee, hip, or shoulder. These scaffolds use two distinct matrix materials. One is a relatively stiff matrix material, designed to withstand and resist a compressive articulating load placed on the joint during the convalescent period, shortly after surgery. The second material comprises a more open and porous matrix, designed to promote maximal rapid generation of new cartilage. The scaffold would support the membrane with a degree of stiffness and resiliency that allows the membrane to mimic a healthy cartilage surface.
U.S. Pat. No. 6,629,997 issued on Oct. 7, 2003, entire contents of which are incorporated herein by reference, discloses a device for surgical implantation to replace damaged tissue in a joint (such as a meniscus in a knee) that is created from a hydrogel that is reinforced by a three-dimensional flexible fibrous mesh. In a meniscal implant, the mesh is exposed at one or more locations around the periphery, to provide anchoring attachments that can be sutured, pinned, or otherwise securely affixed to tissue that surrounds the implant. Articulating surfaces which will rub and slide against cartilage should be coated with a hydrogel layer that is completely smooth and nonabrasive, and made of a material that remains constantly wet.
U.S. Pat. No. 6,800,298 issued on Oct. 5, 2004, entire contents of which are incorporated herein by reference, discloses fluid compositions containing a dextran-based hydrogel with lipids that provides enhanced rheological and tribological properties of such a fluid. Phospholipids are particularly useful in dextran-based compositions for synovial fluid. One phospholipid that can be used advantageously in synovial fluid is dipalmitoyl phosphatidylcholine.
U.S. Pat. No. 6,893,463 issued on May 17, 2005, entire contents of which are incorporated herein by reference, discloses an implantable knee prosthesis including a two-piece body having a substantially elliptical shape in plane and including a first piece and a second piece. The first piece is a tibial piece including a tibial surface. The second piece is a femoral piece including a femoral surface. The first piece and the second piece are mutually slidably engagable and separable.
U.S. Pat. No. 6,905,514 issued on Jun. 14, 2005, entire contents of which are incorporated herein by reference, discloses a replacement device for resurfacing a joint surface of a femur. The custom replacement device is designed to substantially fit the trochlear groove surface of an individual femur. Thereby creating a “customized” replacement device for that individual femur and maintaining the original kinematics of the joint. The top surface is designed so as to maintain centrally directed tracking of the patella perpendicular to the plane established by the distal end of the femoral condyles and aligned with the center of the femoral head.
U.S. Pat. No. 6,960,617 issued on Nov. 1, 2005, entire contents of which are incorporated herein by reference, discloses hydrogels having improved elasticity and mechanical strength properties by subjecting a hydrogel formulation containing a strengthening agent to chemical or physical crosslinking conditions subsequent to initial gel formation. Superporous hydrogels having improved elasticity and mechanical strength properties are similarly obtained whenever the hydrogel formulation is provided with a foaming agent. Interpenetrating networks of polymer chains comprised of primary polymer and strengthening polymer are thereby formed. The primary polymer affords capillary-based water sorption properties while the strengthening polymer imparts significantly enhanced mechanical strength and elasticity to the hydrogel or superporous hydrogel. Suitable strengthening agents can be natural or synthetic polymers, polyelectrolytes, or neutral, hydrophilic polymers.
U.S. Pat. No. 6,994,730 issued on Feb. 7, 2006, entire contents of which are incorporated herein by reference, discloses a method for resurfacing a joint capsule having cartilage and meniscal surfaces such as a knee joint including resecting a central portion of the joint cartilage on one joint member such as the tibia while leaving a meniscal rim attached to the peripheral joint capsule. A cavity is then formed in the bone underlying the central portion of the joint surface such as the lateral tibial surface. A resurfacing implant is then coupled, by cementing for example, to the cavity. A soft prosthetic meniscal implant is then coupled to the remaining meniscal ring such as by suturing.
U.S. Pat. No. 7,008,635 issued on Mar. 7, 2006, entire contents of which are incorporated herein by reference, discloses hydrogels intended for orthopedic applications with a hydrogel formulation which has high strength, toughness, a suitable mechanical modulus and low equilibrium hydration. It may have controlled porosity or degradation time. It can be made to polymerize in situ with high adherence to target tissue or surfaces. A preferred formulation for forming such gels comprises 40 to 80% by weight of a low-molecular weight polar monomer and 30 to 10% of a hydrophilic macromeric crosslinker.
U.S. Pat. No. 7,060,074 issued on Jun. 13, 2006, entire contents of which are incorporated herein by reference, discloses instrumentation for use in minimally invasive unicompartmental knee replacement including a tibial cutting guide for establishing a planar surface along a tibial plateau and a tibial stylus having an anatomic contour for controlling the depth of the planar surface along the tibial plateau. The instrumentation further comprises a posterior resection block for preparing a posterior femoral resection, with a forward portion of the posterior resection block having a configuration corresponding to the configuration of a prosthetic femoral component. Instrumentation comprising a resection block and a resurfacing guide are provided for surgically preparing a femoral condyle to receive a prosthetic femoral component. The instrumentation further includes a resurfacing guide and a resurfacing instrument for resurfacing a femoral condyle to a controlled depth.
U.S. Application publication No. 2001/0043913 published on Nov. 12, 2001, entire contents of which are incorporated herein by reference, discloses a meniscal implant biomaterial made of a novel in situ produced macroporous biomedical polyurethane-amide material based on chain extended isocyanate terminated polyester prepolymer units, wherein the chain extension has been done with at least one dicarboxylic acid or a hydroxy-carboxylic acid.
U.S. Application publication No. 2002/0022884 published on Feb. 21, 2002, entire contents of which are incorporated herein by reference, discloses a device designed for surgical implantation to replace damaged tissue (such as a meniscus in a knee) having a hydrogel component reinforced by a three-dimensional mesh. The mesh component provides strength and structural support for the implant, which has at least one articulating surface, and at least one anchoring surface. In one embodiment, the mesh emerges from one or more selected locations around the peripheral rim of a meniscal implant, to provide anchoring attachments that can be sutured, pinned, clipped, or otherwise securely affixed to the fibrous capsule that surrounds the knee. This composite structure, with hydrogel layers surrounding an embedded mesh component, provides a joint-repair implant with improved anchoring, strength, and performance compared to implants of the prior art.
U.S. Application publication No. 2002/0127264 published on Sep. 12, 2002, entire contents of which are incorporated herein by reference, discloses a method and system for the creation or modification of the wear surface of orthopedic joints, involving the preparation and use of one or more partially or fully preformed and procured components, adapted for insertion and placement into the body and at the joint site. In a preferred embodiment, component(s) can be partially cured and generally formed ex vivo and further formed in vivo at the joint site to enhance conformance and improve long-term performance. In another embodiment, a preformed balloon or composite material can be inserted into the joint site and filled with a flowable biomaterial in situ to conform to the joint site.
U.S. Application publication No. 2004/0133275 published on Jul. 8, 2004, entire contents of which are incorporated herein by reference, discloses a permanent non-resorbable implant allowing surgical replacement of cartilage in articulating joints, using a hydro gel material (such as a synthetic polyacrylonitrile polymer) reinforced by a flexible fibrous matrix. Articulating hydrogel surface(s) are chemically treated to provide a negative electrical charge that emulates the negative charge of natural cartilage, and also can be treated with halogenating, cross-linking, or other chemical agents for greater strength.
U.S. Application publication No. 2004/0195727 published on Oct. 7, 2004, entire contents of which are incorporated herein by reference, discloses a method of making a lubricious polyacrylonitrile knee meniscus implant of a predetermined form and the resulting product.
U.S. Application publication No. 2004/0267371 published on Dec. 30, 2004, entire contents of which are incorporated herein by reference, discloses a prosthetic tibial component for a prosthetic total knee joint, that comprises two constructs, one being a metal base construct that engages the bone and the other being a polyethylene bearing construct that attaches to the metal base construct and articulates with a femoral prosthetic component on the opposing side of the joint. The metal base construct is composed of two different metals, one of which engages the bone surface and the other of which engages the polyethylene bearing construct. The first metal (i.e., the one that engages the bone surface) is selected so as to provide a superior bone-engaging face, while the second metal (i.e., the one that engages the polyethylene bearing construct) is selected so as to provide a superior polyethylene-engaging face.
U.S. Application publication No. 2005/0027307 published on Feb. 3, 2005, entire contents of which are incorporated herein by reference, discloses unitary surgical devices having a pair of fixating mechanisms connected to a base with suture, anchors or pre-formed holes in the base and further including extracellular matrix material either as part of the base or supported on the base. The extracellular matrix material serves as tissue regenerating material. The devices can be used either as an insert to be placed between and approximated to the inner surfaces of the tear or as an insert to replace a void in the meniscus left after a meniscectomy.
U.S. Application publication No. 2005/0033424 published on Feb. 10, 2005, entire contents of which are incorporated herein by reference, discloses a prosthesis for implantation into a knee joint compartment between a femoral condyle and its corresponding tibial plateau which reduces any excessive prosthesis motion. The prosthesis includes a hard body having a generally elliptical shape in plan and a pair of opposed surfaces including a bottom surface and an opposed top surface, the top surface having a first portion which is generally flat.
U.S. Application publication No. 2005/0043808 published on Feb. 24; 2005, entire contents of which are incorporated herein by reference, discloses a method and related composition and apparatus for repairing a tissue site. The method involves the use of a curable polyurethane biomaterial composition having a plurality of parts adapted to be mixed at the time of use in order to provide a flowable composition and to initiate cure. The flowable composition can be delivered using minimally invasive means to a tissue site and there fully cured provide a permanent and biocompatible prosthesis for repair of the tissue site. Further provided are a mold apparatus, e.g., in the form of a balloon or tubular cavity, for receiving a biomaterial composition, and a method for delivering and filling the mold apparatus with a curable composition in situ to provide a prosthesis for tissue repair.
U.S. Application publication No. 2005/0055101 published on Mar. 10, 2005, entire contents of which are incorporated herein by reference, discloses an endoprosthesis having improved self-lubrication mechanisms, the ability to filter the particles from the debris produced by the moving parts, and a new viscoelastic behavior under loading which reduce the transmitted forces. This has been achieved with the use of compressible materials and mechanisms between the fixed bearing and the tibial component, allowing the endoprosthesis to have compressibility under loading, which allows it also to receive or create chambers with an exit to the surface articulating with the femoral condyles.
U.S. Application publication No. 2005/0113840 published on May 26, 2005, entire contents of which are incorporated herein by reference, discloses various method and apparatuses used to perform a resection of a portion of the anatomy for preparation of the implants of a prosthetic. Various resecting member can be used to assist in the resection of an anatomy to provide for implantation of a prosthetic.
U.S. Application publication No. 2005/0137708 published on Jun. 23, 2005, entire contents of which are incorporated herein by reference, discloses a knee joint resurfacing including femoral implant and tibial implant components. The femoral implant components may be attached to the femur using screws or other fixation devices. The femoral implant component may be configured to share loads between cortical and cancellous bone material. The tibial implant components are formed in modular portions which may be assembled within the knee joint and may be free-floating or fixed to the tibial surface.
U.S. Application publication No. 2006/0064169 published on Mar. 23, 2006, entire contents of which are incorporated herein by reference, discloses numerous joint replacement implant embodiments including a total knee replacement implant including a femoral component having a wheel; and a tibial component including a shock-adsorbing component with a piston assembly and spring. The implants contain a cushioning or shock-absorbing member to dampen axial loads and other forces. In many embodiments, fluid is forced rapidly from the device wherein compression and dampening is achieved by valves or other pathways that allow for a slower return of the fluid back into the implant as the pressure is relieved.
U.S. Application publication No. 2006/0155380 published on Jul. 13, 2006, entire contents of which are incorporated herein by reference, discloses a femoral component for a total knee joint replacement having a modular structure including a number of segments, each of the segments having a femoral fixation surface for attachment to the distal end of a femur and at least one assembly surface for joining with an adjacent segment of the modular femoral component.
U.S. Application publication No. 2006/0178497 published on Aug. 10, 2006, entire contents of which are incorporated herein by reference, discloses implantable devices that include biocompatible polyurethane materials. In particular, the disclosed polyurethane materials can maintain desired elastomeric characteristics while exhibiting thermoset-like behavior and can exhibit improved characteristics so as to be suitable in load-bearing applications such as in artificial joints, including total joint replacement applications.
Oka and his associates reported that polyvinyl alcohol hydrogel (PVA-H), ‘a rubber-like gel’, shows its usefulness as an artificial articular cartilage (Proc Inst Mech Eng 2000; 214:59-68). As compared to polyethylene (PE), the PVA-H had a thicker fluid film under higher pressures than polyethylene (PE) did, and PVA-H had a better damping effect and better wear factor. The artificial articular cartilage made from PVA-H could be attached to the underlying bone using a composite osteochondral device made from titanium fibre mesh. The composite osteochondral device became rapidly attached to host bone by ingrowth into the supporting mesh.
Hyaluronic acid and hyaluronates (HA's), such as Synvisc, Hyalgan, Supartz, Orthovisc, Neovisc, Euflexxa/Nuflexxz, Durolane, Fermathron, Suplaysn, are available for injection into joint spaces to provide additional lubrication and treat pain associated with osteoarthritis. HA's in solution are very viscous and therefore the amount of HA per injection (about 2.0 ml) is limited by viscosity. Although injections appear to be effective, these products require multiple injections (usually 3-5) and the effectiveness lasts only for 3-6 months. The present technology is to increase molecular weight of the HA or to crosslink the HA to retard its degradation and clearance from the joint space.
Hence, repairing or replacing a torn meniscus with a meniscus wafer is suggested as a means to relieve the joint pain and to treat the knee joint accordingly. The current invention also discloses devices, methods, formulations, and instruments for treating a joint of a body.